Marine Population Dynamics

This set of vocabulary flashcards covers key concepts in marine population dynamics, including population growth models, distribution patterns, biomass metrics, and ecological case studies like trophic cascades and extinctions.

Population

A group of individuals of the same species occupying a specific area and sharing a gene pool over a certain period of time.

Population Dynamics

The study of how populations of a species change over time, seeking to explain average abundance, fluctuations, and resilience.

Maximum Sustained Yield (MSY)

In fisheries management, the goal of maintaining and maximizing the highest catch that can be taken from a stock over an indefinite period.

Minimum Viable Population (MVP)

A lower bound on the population of a species such that it can survive in the wild.

Carrying Capacity (K)

The maximum sustainable population size of a species in a given area, determined by the amount of available resources such as food, habitat, and water.

Intra-specific competition

Competition between individuals of the same species for limited resources as population density increases.

Inter-specific competition

Competition for limited resources between individuals of different species.

John Damuth (1981)

The scientist who produced the first clear demonstration that population density generally declines with increasing organism body size.

Random Distribution

A distribution pattern where an individual has an equal probability of occurring anywhere in an area, resulting from neutral interactions.

Regular Distribution

A distribution pattern where individuals are uniformly spaced through the environment, often due to antagonistic interactions or local depletion of resources.

Clumped (Aggregated) Distribution

A distribution pattern where individuals live in areas of high local abundance separated by areas of low abundance, often due to attraction to common resources.

Closed Animal Population Model

A simple population model with no immigration or emigration, defined by the formula: $N_{t+1} = N_t + B - M$.

Log Phase

A time of exponential growth in a population, specifically observed in marine microbes.

Stationary Phase

A phase in a closed system where growth reaches a plateau because the number of dying cells equals the number of dividing cells.

Biomass Model (Open System)

A model for harvested species where biomass is calculated as: $B_{t+1} = B_t + R + G - M$, where R is recruitment and G is growth.

Recruitment (R)

The appearance of new, young organisms in a population following a reproductive event, or the maturing of individuals into adult age classes.

Asymptotic Growth

The typical growth pattern of fish characterized by rapid growth in young individuals and reduced growth upon the onset of maturity.

Mortality (M)

The process of death due to natural causes such as predation and disease, typically expressed as a rate for post-recruitment individuals.

Metapopulation

A 'population of populations' consisting of semi-isolated sub-populations periodically connected by dispersal.

Steller’s Sea Cow ($Hydrodamalis gigas$)

A giant sirenian discovered in 1741 and extinct by 1768 due to 'blitzkrieg' hunting and the loss of kelp forests.

Neoextinctions

A term for historical extinctions across human history, suggesting that recorded extinctions are likely underestimated due to geographical bias and decline of taxonomic expertise.

Trophic Cascades

Powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed.

Top-down Cascade

A process where predators reduce the abundance or behavior of their prey, thereby releasing the next lower trophic level from predation or herbivory.

Net Primary Productivity (NPP) in Kelp Forests

The measure of energy production which ranges from $313-900\,g\,C\,m^{-2}\,yr^{-1}$ in ecosystems where sea otters are present to suppress urchins.